/******************************************************
Sessions

(c) 1996 Innobase Oy

Created 6/25/1996 Heikki Tuuri
*******************************************************/

#include "usr0sess.h"

#ifdef UNIV_NONINL
#include "usr0sess.ic"
#endif

#include "trx0trx.h"

/*************************************************************************
Closes a session, freeing the memory occupied by it. */
static void sess_close(
    /*=======*/
    sess_t *sess); /* in, own: session object */

/*************************************************************************
Opens a session. */

sess_t *sess_open(void)
/*===========*/
/* out, own: session object */
{
  sess_t *sess;

#ifdef UNIV_SYNC_DEBUG
  ut_ad(mutex_own(&kernel_mutex));
#endif /* UNIV_SYNC_DEBUG */
  sess = mem_alloc(sizeof(sess_t));

  sess->state = SESS_ACTIVE;

  sess->trx = trx_create(sess);

  UT_LIST_INIT(sess->graphs);

  return (sess);
}

/*************************************************************************
Closes a session, freeing the memory occupied by it. */

static void sess_close(
    /*=======*/
    sess_t *sess) /* in, own: session object */
{
#ifdef UNIV_SYNC_DEBUG
  ut_ad(mutex_own(&kernel_mutex));
#endif /* UNIV_SYNC_DEBUG */
  ut_ad(sess->trx == NULL);

  mem_free(sess);
}

/*************************************************************************
Closes a session, freeing the memory occupied by it, if it is in a state
where it should be closed. */

ibool sess_try_close(
    /*===========*/
    /* out: TRUE if closed */
    sess_t *sess) /* in, own: session object */
{
#ifdef UNIV_SYNC_DEBUG
  ut_ad(mutex_own(&kernel_mutex));
#endif /* UNIV_SYNC_DEBUG */
  if (UT_LIST_GET_LEN(sess->graphs) == 0)
  {
    sess_close(sess);

    return (TRUE);
  }

  return (FALSE);
}
